Numerous heat exchangers are known from the existing art, and are often designed in a ring shape. In most applications, ring-shaped heat exchangers serve to cool a first coolant flowing through the flat piping of the heat exchanger by means of cooling air that is blown by a fan or the like from inside to outside (or vice versa) through cooling ribs situated between the flat pipes.
Likewise in most cases the flat pipes have been bent on their narrow sides, so that a plurality of flat pipes can be situated side-by-side and the laminae or the cooling ribs for the radially flowing cooling air can be placed between them. One example among numerous others was described in DE 37 21 257 C2 which is herein incorporated by reference in its entirety.
A ring-shaped heat exchanger has also already been proposed, whose flat pipes have been bent on their wide sides, which is more easily accomplished in terms of production technique. In this case, however, the cooling air flows axially through the laminae situated between the flat pipes. One such example can be found in DE 3 104 945, FIG. 4. DE 3 104 945 is herein incorporated by reference in its entirety.
Ring-shaped heat exchangers have often been equipped with round or slightly oval pipes, which are easier to bend than flat pipes. The lamellae there are usually flat ribs that have openings through which the pipes have been inserted before being bent. With round pipes the surfaces involved in the heat exchange are smaller than with flat pipes, which worsens their efficiency.
Rotating machine elements may be, for example, clutches or brakes that have a need for cooling. Torque transmitting elements have been addressed, for example,—frequently referred to as wet clutches—that run through a coolant sump, in most cases containing oil, and that fling the coolant away by their rotation. The coolant then runs down the wall of the housing, for example, back into the sump, and there can cool down. There are also numerous publications in this field.